Crimson Spell
DNF @ vol3 ch16 pg22. Skimmed through most parts but the smutty stuff. Not really into this storyline but that just cos it's a personal taste. May pick it back up if there's nothing else to read.
Uwasa no Oujisama
3.5 stars. Main story was ok. Last oneshot (ch 6) was a demon/fantasy story with tentacle play. All stories were fun.
Bouzu to Kumo
2.5 stars. Didn't really get into the storyline or plot. One tentacle sex scene between octopus man/side character and another side character. I'm sure other will find it enjoyable but fantasy isn't really my cuppa and there's very few well written ones that can really engage me.
Uchuu no Mozuku
Like a sci-fi tentacle smut, oneshot. Seems like it could continue and I would read more if it did, but tbh; I'm not dying for updates.
Lilith's Cord
This ones another harem trope but the guy gets possessed by succubus and then goes round having sex with anything that has boobs. Still has an interesting paranormal aspect to story and the smut is hawt, so will continue this series. Be aware of some threesomes,Yuri and sodomy with tentacle scenes. Update ch38: it's getting more interesting. Raising it up to a 4 star.
Perfect Half
Whoa! This looks like it's got everything. Smut, action, dystopian storyline, some yuri scenes. Don't expect romance
Secret X Folder
My Special Squishy Someone
3.5 stars. Very interesting so far. Tentacle is a shapeshifting being and girl heroine is a shy nerd who’s in love with her boss. She’s told she will become a hottie if she lets tentacle penetrate her... so she does. Not cheating but tentacle does service other women while servicing heroine. Both are ignorant to their growing feelings towards each other. Update: be warned, sh!t gets really stupid towards the end, dumb decisions, dumb actions and really unnecessary scenes to add taboo, smut and rape to what could have been a cute storyline
Akuma To Issho